/*
 * Copyright (c) 2002, 2003, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
 *
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 *
 *
 *
 *
 *
 *
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 */
package com.sun.java.swing.plaf.gtk;

import javax.swing.plaf.synth.ColorType;
import java.awt.Color;
import javax.swing.plaf.ColorUIResource;

/**
 * @author Scott Violet
 */
public class GTKColorType extends ColorType {

  // GTK allows you to specify the foreground and background in a
  // gtkrc, the rest (dark, mid, light) are calculated from these
  // values.
  public static final ColorType LIGHT = new GTKColorType("Light");
  public static final ColorType DARK = new GTKColorType("Dark");
  public static final ColorType MID = new GTKColorType("Mid");
  public static final ColorType BLACK = new GTKColorType("Black");
  public static final ColorType WHITE = new GTKColorType("White");

  public static final int MAX_COUNT;

  private static final float[] HLS_COLORS = new float[3];
  private static final Object HLS_COLOR_LOCK = new Object();

  static {
    MAX_COUNT = WHITE.getID() + 1;
  }

  private static int hlsToRGB(float h, float l, float s) {
    float m2 = (l <= .5f) ? (l * (1 + s)) : (l + s - l * s);
    float m1 = 2.0f * l - m2;
    float r, g, b;

    if (s == 0.0) {
      if (h == 0.0) {
        r = g = b = l;
      } else {
        r = g = b = 0;
      }
    } else {
      r = hlsValue(m1, m2, h + 120);
      g = hlsValue(m1, m2, h);
      b = hlsValue(m1, m2, h - 120);
    }
    return (((int) (r * 255)) << 16) | (((int) (g * 255.0)) << 8) |
        ((int) (b * 255));
  }

  private static float hlsValue(float n1, float n2, float h) {
    if (h > 360) {
      h -= 360;
    } else if (h < 0) {
      h += 360;
    }
    if (h < 60) {
      return n1 + (n2 - n1) * h / 60.0f;
    } else if (h < 180) {
      return n2;
    } else if (h < 240) {
      return n1 + (n2 - n1) * (240.0f - h) / 60.0f;
    }
    return n1;
  }

  /**
   * Converts from RGB color space to HLS colorspace.
   */
  private static float[] rgbToHLS(int rgb, float[] hls) {
    float r = ((rgb & 0xFF0000) >> 16) / 255.0f;
    float g = ((rgb & 0xFF00) >> 8) / 255.0f;
    float b = (rgb & 0xFF) / 255.0f;

        /* calculate lightness */
    float max = Math.max(Math.max(r, g), b);
    float min = Math.min(Math.min(r, g), b);
    float l = (max + min) / 2.0f;
    float s = 0;
    float h = 0;

    if (max != min) {
      float delta = max - min;
      s = (l <= .5f) ? (delta / (max + min)) : (delta / (2.0f - max - min));
      if (r == max) {
        h = (g - b) / delta;
      } else if (g == max) {
        h = 2.0f + (b - r) / delta;
      } else {
        h = 4.0f + (r - g) / delta;
      }
      h *= 60.0f;
      if (h < 0) {
        h += 360.0f;
      }
    }
    if (hls == null) {
      hls = new float[3];
    }
    hls[0] = h;
    hls[1] = l;
    hls[2] = s;
    return hls;
  }

  /**
   * Creates and returns a new color derived from the passed in color.
   * The transformation is done in the HLS color space using the specified
   * arguments to scale.
   *
   * @param color Color to alter
   * @param hFactory Amount to scale the hue
   * @param lFactor Amount to scale the lightness
   * @param sFactory Amount to sacle saturation
   * @return newly created color
   */
  static Color adjustColor(Color color, float hFactor, float lFactor,
      float sFactor) {
    float h;
    float l;
    float s;

    synchronized (HLS_COLOR_LOCK) {
      float[] hls = rgbToHLS(color.getRGB(), HLS_COLORS);
      h = hls[0];
      l = hls[1];
      s = hls[2];
    }
    h = Math.min(360, hFactor * h);
    l = Math.min(1, lFactor * l);
    s = Math.min(1, sFactor * s);
    return new ColorUIResource(hlsToRGB(h, l, s));
  }

  protected GTKColorType(String name) {
    super(name);
  }
}
